Sheep skin odor improves trap captures of mosquito vectors of Rift Valley fever

Smelly interactions: host-borne volatile organic compounds triggering behavioural responses in mosquitoes, sand flies, and ticks

Volatile organic compounds (VOCs) are chemicals emitted as products of cell metabolism, which reflects the physiological and pathological conditions of any living organisms. These compounds play a key role as olfactory cues for arthropod vectors such as mosquitoes, sand flies, and ticks, which act in the transmission of pathogens to many animal species, including humans. Some VOCs may influence arthropod behaviour, e.g., host preference and oviposition site selection for gravid females. Furthermore, deadly vector-borne pathogens such as Plasmodium falciparum and Leishmania infantum are suggested to manipulate the VOCs profile of the host to make them more attractive to mosquitoes and sand fly vectors, respectively. Under the above circumstances, studies on these compounds have demonstrated their potential usefulness for investigating the behavioural response of mosquitoes, sand flies, and ticks toward their vertebrate hosts, as well as potential tools for diagnosis of vector-borne diseases (VBDs). Herein, we provide an account for scientific data available on VOCs to study the host seeking behaviour of arthropod vectors, and their usefulness as attractants, repellents, or tools for an early diagnosis of VBDs.

Studies on the Volatiles Composition of Stored Sheep Wool, and Attractancy toward Aedes aegypti Mosquitoes

To discover new natural materials for insect management, commercially available stored sheep wool was investigated for attractancy to female adult Aedes aegypti mosquitoes. The volatiles from sheep wool were collected by various techniques of headspace (HS) extractions and hydrodistillation. These extracts were analyzed using gas chromatography-mass spectrometry (GC-MS) and gas chromatography-flame ionization detector (GC-FID) coupled with GC-MS. Fifty-two volatile compounds were detected, many of them known for their mosquito attractant activity. Seven compounds were not previously reported in sheep products. The volatile composition of the extracts varied significantly across collections, depending on the extraction techniques or types of fibers applied. Two types of bioassay were conducted to study attractancy of the sheep wool volatiles to mosquitoes: laboratory bioassays using glass tubes, and semi-field bioassays using large, screened outdoor cages. In bioassays with glass tubes, the sheep wool hydrodistillate and its main component, thialdine, did not show any significant attractant activity against female adult Ae. aegypti mosquitoes. Semi-field bioassays in two large screened outdoor cages, each equipped with a U.S. Centers for Disease Control (CDC) trap and the various bait setups with Vortex apparatus, revealed that vibrating wool improved mosquito catches compared to the setups without wool or with wool but not vibrating. Sheep wool, when vibrated, may release intensively volatile compounds, which could serve as olfactory cues, and play significant role in making the bait attractive to mosquitoes. Sheep wool is a readily available, affordable, and environment-friendly material. It should have the potential to be used as a mosquito management and surveillance component in dynamic bait setups.

Species Variety of the Calf and Human-Attracted Mosquitoes in Southwest Iran

Background:

Any mosquito control methods requires precise information about population dynamics, variety, biology and mosquito habitat. This research assessed Culicid mosquitoes’ attraction to a human host and a calf to better understand their behavior.

Methods:

Adult mosquitoes were sampled in 22 weeks in southwestern Iran’s Nur Ali Village from May to October 2015. The mosquitoes were drawn to the person and calf as bait, while the unbaited trap was also used. A substantial statistical difference between attracted mosquitoes to the hosts was determined in the T-test.

Results:

Within 22 weeks, 29821 mosquitoes were captured. Only 9% were collected from the human baited net trap, 89.1% from the calf baited net trap, and 1.9% from the unbaited net trap. The number of collected female mosquitoes was statistically significantly higher using the calf baited net trap of the total mosquitoes, 916 were randomly identified at the species level by local identification keys. Of these, 63 were Anopheles stephensi (human: 16%, calf: 75% and unbaited: 9%), 83 An. pulcherrimus (human: 27%, calf: 60% and unbaited: 13%), 118 Aedes caspius (human: 24%, calf: 69% and unbaited: 7%), 493 Culex tritaeniorhynchus (human: 52%, calf: 37% and unbaited: 11%), 153 Cx. quinquefasciatus (human: 44%, calf: 47% and unbaited: 9%), and 6 Cx. theileri (human: 33%, calf: 50% and unbaited: 17%).

Conclusion:

The obtained results here provide useful insights into the mosquito population and the possibility of using this information as an essential part of integrated vector management regarding the reemergence of malaria or other mosquito-borne.

Urban mosquitoes and filamentous green algae: their biomonitoring role in heavy metal pollution in open drainage channels in Nairobi industrial area, Kenya

Background

Industrial wastewater is a human health hazard upon exposure. Aquatic organisms in contaminated wastewater may accumulate the toxic elements with time. Human population living in informal settlements in Nairobi industrial area risk exposure to such toxic elements. Biomonitoring using aquatic organisms in open drainage channels can be key in metal exposure assessment. Levels of Mercury (Hg), Lead (Pb), Chromium (Cr), Cadmium (Cd), Thallium (Tl), and Nickel (Ni) were established in samples of wastewater, filamentous green algae (Spirogyra) and mosquitoes obtained from open drainage channels in Nairobi industrial area, Kenya.

Results

Pb, Cr, & Ni levels ranged from 3.08 to 15.31 µg/l while Tl, Hg, & Cd ranged from 0.05 to 0.12 µg/l in wastewater. The Pb, Cr, Ni, & Cd levels were above WHO, Kenya & US EPA limits for wastewater but Hg was not. Pb, Cr, Tl, & Ni levels in assorted field mosquitoes were 1.3–2.4 times higher than in assorted laboratory-reared mosquitoes. Hg & Cd concentrations in laboratory-reared mosquitoes (0.26 mg/kg & 1.8 mg/kg respectively) were higher than in field mosquitoes (0.048 mg/kg & 0.12 mg/kg respectively). The levels of Pb, Cr, & Ni were distinctively higher in field mosquito samples than in wastewater samples from the same site. Pb, Cr, Ni, Cd & Hg levels in green filamentous Spirogyra algae were 110.62, 29.75, 14.45, 0.44, & 0.057 mg/kg respectively. Correlation for Pb & Hg (r (2) = 0.957; P < 0.05); Cd & Cr (r (2) = 0.985; P < 0.05) in algae samples was noted. The metal concentrations in the samples analyzed were highest in filamentous green algae and least in wastewater.

Conclusion

Wastewater, mosquitoes, and filamentous green algae from open drainage channels and immediate vicinity, in Nairobi industrial area (Kenya) contained Hg, Pb, Cr, Cd, Tl, and Ni. Mosquitoes in urban areas and filamentous green algae in open drainage channels can play a role of metal biomonitoring in wastewater. The potential of urban mosquitoes transferring heavy metals to human population from the contaminated wastewater should be investigated.

Large herbivore loss has complex effects on mosquito ecology and vector-borne disease risk

Loss of biodiversity can affect transmission of infectious diseases in at least two ways: by altering host and vector abundance or by influencing host and vector behaviour. We used a large herbivore exclusion experiment to investigate the effects of wildlife loss on the abundance and feeding behaviour of mosquito vectors and to explore consequences for vector-borne disease transmission. Large herbivore loss affected both mosquito abundance and blood-feeding behaviour. For Aedes mcintoshi, the dominant mosquito species in our study and a primary vector of Rift Valley fever virus (RVFV), abundance decreased with large herbivore loss, while blood feeding on humans increased. Despite an elevated human biting rate in the absence of large herbivores, we estimated that the potential for RVFV transmission to humans doubles in the presence of large herbivores. These results demonstrate that multiple effects of biodiversity loss on vectors can lead to counterintuitive outcomes for human disease risk.

Differential response to plant- and human-derived odorants in field surveillance of the dengue vector, Aedes aegypti

Linalool oxide (LO) and hexanoic acid (HA) represent plant- and human-derived odorants, respectively, previously found as attractants for the dengue vector Aedes aegypti. Here, we investigated if a blend of both compounds can improve captures of this mosquito species in field trials in two dengue endemic sites, Kilifi and Busia Counties in Kenya. Ae. aegypti captures were significantly higher in Kilifi than Busia (χ²_1,142 = 170.63, P < 0.0001) and varied by treatments (χ²_5,137 = 151.19, P = 0.002). We found that CO₂-baited BG Sentinel traps combined with a blend of both odorants decreased Ae. aegypti captures about 2- to 4-fold compared to captures with the individual compounds (LO or HA) used as positive controls. This was the case for all blends of LO and HA, irrespective of the doses tested. Our findings indicate that combining plant- and human-derived odors may elicit a masking effect in trapping Ae. aegypti. These results partly corroborate previous findings for malaria mosquitoes which showed that combining lures from both host sources either decreases or increases trap catches depending on the dose. Further investigations in the usefulness of combining plant and animal odorants in mosquito trapping are therefore necessary.

Aedes vector-host olfactory interactions in sylvatic and domestic dengue transmission environments

Interactions between Aedes (Stegomyia) species and non-human primate (NHP) and human hosts govern the transmission of the pathogens, dengue, zika, yellow fever and chikungunya viruses. Little is known about Aedes mosquito olfactory interactions with these hosts in the domestic and sylvatic cycles where these viruses circulate. Here, we explore how the different host-derived skin odours influence Aedes mosquito responses in these two environments. In field assays, we show that the cyclic ketone cyclohexanone is a signature cue for Aedes mosquitoes to detect the NHP baboon, sykes and vervet, whereas for humans, it is the unsaturated aliphatic keto-analogue 6-methyl-5-hepten-2-one (sulcatone). We find that in the sylvatic environment, CO₂-baited traps combined with either cyclohexanone or sulcatone increased trap catches of Aedes mosquitoes compared to traps either baited with CO₂ alone or CO₂ combined with NHP- or human-derived crude skin odours. In the domestic environment, each of these odourants and crude human skin odours increased Aedes aegypti catches in CO₂-baited traps. These results expand our knowledge on the role of host odours in the ecologies of Aedes mosquitoes, and the likelihood of associated spread of pathogens between primates and humans. Both cyclohexanone and sulcatone have potential practical applications as lures for monitoring Aedes disease vectors.

Zebra skin odor repels the savannah tsetse fly, Glossina pallidipes (Diptera: Glossinidae)

BACKGROUND

African trypanosomosis, primarily transmitted by tsetse flies, remains a serious public health and economic challenge in sub-Saharan Africa. Interventions employing natural repellents from non-preferred hosts of tsetse flies represent a promising management approach. Although zebras have been identified as non-preferred hosts of tsetse flies, the basis for this repellency is poorly understood. We hypothesized that zebra skin odors contribute to their avoidance by tsetse flies.

METHODOLOGY/PRINCIPAL FINDINGS

We evaluated the effect of crude zebra skin odors on catches of wild savannah tsetse flies (Glossina pallidipes Austen, 1903) using unbaited Ngu traps compared to the traps baited with two known tsetse fly management chemicals; a repellent blend derived from waterbuck odor, WRC (comprising geranylacetone, guaiacol, pentanoic acid and δ-octalactone), and an attractant comprising cow urine and acetone, in a series of Latin square-designed experiments. Coupled gas chromatography-electroantennographic detection (GC/EAD) and GC-mass spectrometry (GC/MS) analyses of zebra skin odors identified seven electrophysiologically-active components; 6-methyl-5-hepten-2-one, acetophenone, geranylacetone, heptanal, octanal, nonanal and decanal, which were tested in blends and singly for repellency to tsetse flies when combined with Ngu traps baited with cow urine and acetone in field trials. The crude zebra skin odors and a seven-component blend of the EAD-active components, formulated in their natural ratio of occurrence in zebra skin odor, significantly reduced catches of G. pallidipesby 66.7% and 48.9% respectively, and compared favorably with the repellency of WRC (58.1%- 59.2%). Repellency of the seven-component blend was attributed to the presence of the three ketones 6-methyl-5-hepten-2-one, acetophenone and geranylacetone, which when in a blend caused a 62.7% reduction in trap catch of G. pallidipes.

CONCLUSIONS/SIGNIFICANCE

Our findings reveal fundamental insights into tsetse fly ecology and the allomonal effect of zebra skin odor, and potential integration of the three-component ketone blend into the management toolkit for tsetse and African trypanosomosis control.

Independent and interactive effect of plant- and mammalian- based odors on the response of the malaria vector, Anopheles gambiae

Several studies have shown that odors of plant and animal origin can be developed into lures for use in surveillance of mosquito vectors of infectious diseases. However, the effect of combining plant- and mammalian-derived odors into an improved lure for monitoring both nectar- and blood-seeking mosquito populations in traps is yet to be explored. Here we used both laboratory dual choice olfactometer and field assays to investigate responses of the malaria vector, Anopheles gambiae, to plant- and mammalian-derived compounds and a combined blend derived from these two odor sources. Using subtractive bioassays in dual choice olfactometer we show that a 3-component terpenoid plant-derived blend comprising (E)-linalool oxide, β-pinene, β-ocimene was more attractive to females of An. gambiae than (E)-linalool oxide only (previously found attractive in field trials) and addition of limonene to this blend antagonized its attractiveness. Likewise, a mammalian-derived lure comprising the aldehydes heptanal, octanal, nonanal and decanal, was more preferred than (E)-linalool oxide. Surprisingly, combining the plant-derived 3-component blend with the mammalian derived 4-component blend attracted fewer females of An. gambiae than the individual blends in laboratory assays. However, this pattern was not replicated in field trials, where we observed a dose-dependent effect on trap catches while combining both blends with significantly improved trap catches at higher doses. The observed dose-dependent attractiveness for An. gambiae has practical implication in the design of vector control strategies involving kairomones from plant- and mammalian-based sources.

Composition and Genetic Diversity of Mosquitoes (Diptera: Culicidae) on Islands and Mainland Shores of Kenya's Lakes Victoria and Baringo

The Lake Baringo and Lake Victoria regions of Kenya are associated with high seroprevalence of mosquito-transmitted arboviruses. However, molecular identification of potential mosquito vector species, including morphologically identified ones, remains scarce. To estimate the diversity, abundance, and distribution of mosquito vectors on the mainland shores and adjacent inhabited islands in these regions, we collected and morphologically identified adult and immature mosquitoes and obtained the corresponding sequence variation at cytochrome c oxidase 1 (COI) and internal transcribed spacer region 2 (ITS2) gene regions. A total of 63 species (including five subspecies) were collected from both study areas, 47 of which have previously been implicated as disease vectors. Fourteen species were found only on island sites, which are rarely included in mosquito diversity surveys. We collected more mosquitoes, yet with lower species composition, at Lake Baringo (40,229 mosquitoes, 32 species) than at Lake Victoria (22,393 mosquitoes, 54 species). Phylogenetic analysis of COI gene sequences revealed Culex perexiguus and Cx tenagius that could not be distinguished morphologically. Most Culex species clustered into a heterogeneous clade with closely related sequences, while Culex pipiens clustered into two distinct COI and ITS2 clades. These data suggest limitations in current morphological identification keys. This is the first DNA barcode report of Kenyan mosquitoes. To improve mosquito species identification, morphological identifications should be supported by their molecular data, while diversity surveys should target both adults and immatures. The diversity of native mosquito disease vectors identified in this study impacts disease transmission risks to humans and livestock.

Mosquito host choices on livestock amplifiers of Rift Valley fever virus in Kenya

Background

Animal hosts may vary in their attraction and acceptability as components of the host location process for assessing preference, and biting rates of vectors and risk of exposure to pathogens. However, these parameters remain poorly understood for mosquito vectors of the Rift Valley fever (RVF), an arboviral disease, and for a community of mosquitoes.

Methods

Using three known livestock amplifiers of RVF virus including sheep, goat and cattle as bait in enclosure traps, we investigated the host-feeding patterns for a community of mosquitoes in Naivasha, an endemic area of Rift Valley fever (RVF), in a longitudinal study for six months (June–November 2015). We estimated the incidence rate ratios (IRR) where mosquitoes chose cow over the other livestock hosts by comparing their attraction (total number collected) and engorgement rate (proportion freshly blood-fed) on these hosts.

Results

Overall, significant differences were observed in host preference parameters for attraction (F_2,15 = 4.1314, P = 0.037) and engorgement (F_2,15 = 6.24, P = 0.01) with cow consistently attracting about 3-fold as many mosquitoes as those engorged on sheep (attraction: IRR = 2.9, 95 % CI 1.24–7.96; engorgement: IRR = 3.2, 95 % CI = 1.38–7.38) or goat (attraction: IRR = 2.7, 95 % CI 1.18–7.16; engorgement: IRR = 3.28, 95 % CI 1.47–7.53). However, there was no difference between the attraction elicited by sheep and goat (IRR = 1.08; 95 % CI 0.35–3.33 or engorgement rate (IRR = 0.96, 95 % CI  0.36–2.57).

Conclusion

Despite the overall attractive pattern to feed preferentially on cows, the engorgement rate was clearly independent of the number attracted for certain mosquito species, notably among the flood water Aedes spp., largely incriminated previously as primary vectors of RVF. Our findings suggest that insecticide treated cattle (ITC) can be exploited in enclosure traps as contact bait in the monitoring and control of disease-causing mosquitoes in RVF endemic areas.

Linalool oxide: generalist plant based lure for mosquito disease vectors

BACKGROUND

Lack of effective vaccines and therapeutics for important arboviral diseases such as Rift Valley fever (RVF) and dengue, necessitates continuous monitoring of vector populations for infections in them. Plant-based lures as surveillance tools has the potential of targeting mosquitoes of both sexes and females of varied physiological states; yet such lures are lacking for vectors of these diseases. Here, we present evidence of the effectiveness of linalool oxide (LO), a single plant-based lure previously developed for malaria vectors in trapping RVF vectors, Aedes mcintoshi and Aedes ochraceus, and dengue vector, Aedes aegypti.

METHODS

For RVF vectors, we used CDC traps to evaluate the performance of LO against three vertebrate-based lures: CO2 (dry ice), BioGent (BG) lure, and HONAD (a blend of aldehydes) in 2 experiments with Completely Randomized design: 1) using unlit CDC traps baited separately with LO, HONAD and BG-lure, and unlit CDC trap + CO2 and lit CDC trap as controls, 2) similar treatments but with inclusion of CO2 to all the traps. For dengue vectors, LO was evaluated against BG lure using BG sentinel traps, in a 3 × 6 Latin Square design, first as single lures and then combined with CO2 and traps baited with CO2 included as controls. Trap captures were compared between the treatments using Chi square and GLM.

RESULTS

Low captures of RVF vectors were recorded for all lures in the absence of CO2 with no significant difference between them. When combined with CO2, LO performance in trapping these vectors was comparable to BG-lure and HONAD but it was less effective than the lit CDC trap. In the absence of CO2, LO performed comparably with the BG-lure in trapping female Ae. aegypti, but with significantly higher males recorded in traps baited with the plant-based lure. When CO2 was added, LO was significantly better than the BG-lure with a 2.8- fold increase in captures of male Ae. aegypti.

CONCLUSIONS

These results highlight the potential of LO as a generalist plant-based lure for mosquito disease vectors, pending further assessment of possible specificity in their response profile to the different stereoisomers of this compound.

Population genetics of two key mosquito vectors of Rift Valley Fever virus reveals new insights into the changing disease outbreak patterns in Kenya

Rift Valley fever (RVF) outbreaks in Kenya have increased in frequency and range to include northeastern Kenya where viruses are increasingly being isolated from known (Aedes mcintoshi) and newly-associated (Ae. ochraceus) vectors. The factors contributing to these changing outbreak patterns are unclear and the population genetic structure of key vectors and/or specific virus-vector associations, in particular, are under-studied. By conducting mitochondrial and nuclear DNA analyses on >220 Kenyan specimens of Ae. mcintoshi and Ae. ochraceus, we uncovered high levels of vector complexity which may partly explain the disease outbreak pattern. Results indicate that Ae. mcintoshi consists of a species complex with one of the member species being unique to the newly-established RVF outbreak-prone northeastern region of Kenya, whereas Ae. ochraceus is a homogeneous population that appears to be undergoing expansion. Characterization of specimens from a RVF-prone site in Senegal, where Ae. ochraceus is a primary vector, revealed direct genetic links between the two Ae. ochraceus populations from both countries. Our data strongly suggest that unlike Ae. mcintoshi, Ae. ochraceus appears to be a relatively recent, single 'introduction' into Kenya. These results, together with increasing isolations from this vector, indicate that Ae. ochraceus will likely be of greater epidemiological importance in future RVF outbreaks in Kenya. Furthermore, the overall vector complexity calls into question the feasibility of mosquito population control approaches reliant on genetic modification.

Despite the threat posed by Rift Valley fever (RVF), poor understanding of the disease epidemiology exists with respect to vector population structure in relation to differential outbreak patterns and future vector genetic control. Here, nuclear and mtDNA data reveal genetic complexities of RVF key vectors (Aedes mcintoshi and Ae. ochraceus) partly explaining the disease outbreak pattern in Kenya. While anticipating population differentiation, we found that the hitherto known Ae. mcintoshi in fact comprises a species complex, with one unique species restricted to northeastern Kenya where outbreaks have increased in frequency with evidence for new involvement of Ae. ochraceus in RVF epidemiology. We infer a relatively recent, single “introduction” of Ae. ochraceus into Kenya with genetic links to a RVF hotspot in Senegal. Ultimately, our findings provide an understanding of how the two primary mosquito vector species impact RVF, which is critical to the potential prediction of the emergence and spread of the disease in Kenya.

Field evaluation of natural human odours and the biogent-synthetic lure in trapping Aedes aegypti, vector of dengue and chikungunya viruses in Kenya

BACKGROUND

Methods currently used in sampling adult Aedes aegypti, the main vector of dengue and chikungunya viruses are limited for effective surveillance of the vector and accurate determination of the extent of virus transmission during outbreaks and inter - epidemic periods. Here, we document the use of natural human skin odours in baited traps to improve sampling of adult Ae. aegypti in two different endemic areas of chikungunya and dengue in Kenya - Kilifi and Busia Counties. The chemistry of the volatiles released from human odours and the Biogent (BG)-commercial lure were also compared.

METHODS

Cotton socks and T-shirts were used to obtain natural human skin volatiles from the feet and trunk of three volunteers (volunteers 1 and 2 in Kilifi and volunteers 2 and 3 in Busia). Using Latin square design, we compared the efficacies of BG sentinel traps baited with carbon dioxide plus (a) no bait, (b) human feet volatiles, (c) human trunk volatiles each against (c) a control (Biogent commercial lure) at the two sites. Coupled gas chromatography-mass spectrometry (GC-MS) was used to identify and compare candidate attractants released by the commercial lure and human odours.

RESULTS

Ae. aegypti captured in the trap baited with feet odours from volunteer 2 and trunk odours from the same volunteer were significantly higher than in the control trap in Busia and Kilifi respectively, [IRR = 5.63, 95% CI: 1.15 - 28.30, p = 0.030] and [IRR = 3.99, 95% CI: 0.95-16.69, p = 0.049]. At both sites, Ae. aegypti captures in traps baited with either the feet or trunk odours from volunteers 1 and 3 were not significantly different from the control. Major qualitative differences were observed between the chemical profiles of human odours and the commercial BG-lure. Aldehydes, fatty acids and ketones dominated human odour profiles, whereas the BG-lure released mainly hexanoic acid.

CONCLUSIONS

Our results suggest that additional candidate attractants are present in human skin volatiles which can help to improve the efficacy of lures for trapping and surveillance of Ae. aegypti.

Common host-derived chemicals increase catches of disease-transmitting mosquitoes and can improve early warning systems for Rift Valley fever virus

Rift Valley fever (RVF), a mosquito-borne zoonosis, is a major public health and veterinary problem in sub-Saharan Africa. Surveillance to monitor mosquito populations during the inter-epidemic period (IEP) and viral activity in these vectors is critical to informing public health decisions for early warning and control of the disease. Using a combination of field bioassays, electrophysiological and chemical analyses we demonstrated that skin-derived aldehydes (heptanal, octanal, nonanal, decanal) common to RVF virus (RVFV) hosts including sheep, cow, donkey, goat and human serve as potent attractants for RVFV mosquito vectors. Furthermore, a blend formulated from the four aldehydes and combined with CO₂-baited CDC trap without a light bulb doubled to tripled trap captures compared to control traps baited with CO₂ alone. Our results reveal that (a) because of the commonality of the host chemical signature required for attraction, the host-vector interaction appears to favor the mosquito vector allowing it to find and opportunistically feed on a wide range of mammalian hosts of the disease, and (b) the sensitivity, specificity and superiority of this trapping system offers the potential for its wider use in surveillance programs for RVFV mosquito vectors especially during the IEP.

Enzootic transmission of arboviral diseases such as Rift Valley Fever (RVF) continues to occur at a low intensity among mosquito vectors in Kenya, which may remain undetected by most monitoring programs unless very sensitive tools are employed to detect virus activity before an outbreak occurs. Here, we report a more sensitive and mosquito-specific surveillance trapping system for RVF virus (RVFV) mosquito vectors based on mammalian-skin derived semiochemicals. We show that RVFV mosquito vectors detect similar components (heptanal, octanal, nonanal, decanal) in the skin of RVFV mammalian hosts. In field trials, each of these compounds when combined with CO₂ increased captures of these mosquito vectors in a dose-dependent manner. Additionally, a blend formulated from optimal attractive dose of each of these compounds combined with CO₂ significantly increased trap captures compared to control traps baited with CO₂ alone. The four-component blend attracted multiple mosquito vectors of the disease under field conditions suggesting that a trapping system based on this formulation offers opportunity for its use as a tool for RVFV vector surveillance.